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K Katoch

Publications and source records attributed to K Katoch.

At least 55 records · Page 3Linked to original sources
PubMed1990

Terminal complement complex in plasma of leprosy patients.

A study was carried out to find out the difference in the levels of circulating terminal complement complex between healthy volunteers and the untreated leprosy patients by using double antibody sandwich ELISA. In addition, the levels of terminal complement complex in lepromatous patients with and without reaction were also compared. None of the group showed any significant difference in the levels of circulating terminal complement complex. These findings suggest that complement may not play a direct role in tissue damage in leprosy.

Complement Activation↗
PubMed1990

Activation of complement by circulating immune complexes isolated from leprosy patients.

Circulating immune complexes isolated from different types of leprosy sera as polyethylene glycol (PEG) precipitates were found to be efficient activators of the alternative pathway of complement. PEG precipitates from BL/LL leprosy patients and those with erythema nodosum leprosum were found to activate both the classical pathway and the alternative pathway of complement efficiently, while PEG precipitates from TT/BT leprosy patients and borderline tuberculoid patients in reaction were found to active the alternative pathway of complement but not the classical pathway. No significant differences were observed between the PEG precipitates from reactional and nonreactional TT/BT and BL/LL patients in their complement activating ability.

Antigen-Antibody Complex↗
PubMed1989

CD1-positive epidermal Langerhans cells in skin reactions to autologous peripheral-blood-derived mononuclear cells in leprosy patients.

A comparison was made on the characteristics of the infiltrates, the number and distribution of CD1-positive epidermal Langerhans cells (LC) at the sites of skin reaction induced by autologous peripheral-blood-derived mononuclear cells (PBMC) in leprosy patients. Clinically and histologically, the skin reaction was well expressed in tuberculoid patients as compared to lepromatous patients, erythema nodosum leprosum (ENL) patients and contacts. The quantum of lymphocytes in the infiltrates was maximal in the tuberculoid patients and it was minimal in lepromatous and ENL patients. The number and distribution of LC in the tuberculoid patients was significantly higher in the PBMC-inoculated sites as compared to control sites over 24 h. In contrast, no difference in the number and distribution of LC was noticed in the lepromatous and ENL patients. These observations indicate that the lymphocytes of tuberculoid patients in contrast to lepromatous leprosy patients are capable of sustenance in the local micro-environments of the skin and an effective interaction may be possible between LC and PBMC.

Antigens, CD1↗
PubMed1989

Effect of chemotherapy on viability of Mycobacterium leprae as determined by ATP content, morphological index and FDA-EB fluorescent staining.

Viable bacterial populations were estimated in bacilli purified from 105 biopsies from 40 untreated and 65 multibacillary leprosy patients treated with multidrug therapy (MDT) for varying periods. The bacilli were purified and viability was determined by ATP content, morphological index (MI), and fluorescein diacetate-ethidium bromide (FDA-EB) staining. Viable populations were calculated, taking 3.58 x 10(-15) g/solid bacillus as the mean ATP content of a viable unit of Mycobacterium leprae. The proportion of viable bacilli was also estimated in the same specimens using solid-staining (MI) and green-staining bacilli by the FDA-EB method. In the untreated cases, the positive viability by ATP assay was 100%, 92% by MI, and 100% by FDA-EB. ATP content per solid bacillus was relatively constant, which was not the case with ATP content per green-staining bacillus. While the MI was zero in all cases, viable bacilli could still be detected by ATP estimations in 5 of the 32 (16%) patients after 2 years of MDT and in 1 of the 20 (5%) patients after 3 years of MDT. No viable bacilli could be detected even by this method beyond 3 years of MDT. On the other hand, green-staining bacilli were demonstrable in 7/32 (22%) of cases after 2 years of MDT, 2/20 (10%) after 3 years of MDT, and 1/13 (8%) after more than 3 years of treatment, indicating that the FDA-EB staining and ATP assay did not detect the same populations. A determination of the ATP content of M. leprae could be used as a reliable and sensitive tool for determining viability of the bacilli.

Adenosine Triphosphate↗
PubMed1989

Immunotherapy of treated BL/LL cases with BCG: histopathological, immunohistological and bacteriological assessments.

The persistence of dead as well as viable bacteria is an important therapeutic problem in multibacillary leprosy. In highly bacillated patients, viable bacteria are detectable in 10-15% of cases after 2 years of treatment and none of these cases became smear negative by 2 years of recommended multidrug therapy (MTD). Immunotherapy trials using BCG (0.1 mg) by intradermal route have been undertaken in cases who had MDT for 2 years and who had viable bacilli by ATP photometry and/or FDA-EB staining. Biopsies and smears were taken from local as well as distant sites at 0.4 weeks and 6 months after BCG vaccination. Biopsies were processed for ATP counts, FDA-EB staining, histopathology and immunohistology for cell types at 0.4 weeks. There was transient effect on BI, ATP counts, FDA-EB staining at local as well as distant sites in some cases. Histopathology and immunohistological findings suggest that there is tendency to form epithelioid cell granuloma at local site in all cases and at distal sites in some. There was infiltration of subepidermal zone in one case, 4 weeks after vaccination. BCG may be of use as potential immunotherapeutic agent but its usefulness needs to be investigated in depth preferably in the beginning or early phases of chemotherapy and with also repeated inoculations.

BCG Vaccine↗
PubMed1989

Studies on energy synthesis in M. leprae.

ATP measurements have been earlier used to study the effect of various nutrients on the growth and multiplication of M. leprae. In a preliminary study, we had observed that glycerol and asparagine stimulated the ATP synthesis by M. leprae but this was marginal and not sustained. We have extended the study to investigate the role of various environmental factors which could affect this ATP synthesis. It has been observed that ATP synthesis was better and sustained for a longer period i.e. upto 2 weeks if the M. leprae were incubated at pH 6-6.5 and at 30-33 degrees C in the modified Dubos and Sauton's media. The pH and temperature above these values were suboptimal. It is concluded that temperature and pH are important factors for maintenance and synthesis of ATP by M. leprae.

Adenosine Triphosphate↗
PubMed1989

Results of a modified WHO regimen in highly bacilliferous BL/LL patients.

A regimen consisting of 600 mg of rifampin once a month, 100 mg of clofazimine on alternate days, and 100 mg of dapsone daily was used in 56 untreated, highly bacillated borderline lepromatous/lepromatous (BL/LL) patients with an average bacterial index (BI) of 4.45. Treatment was continued until skin-smear negativity. After 2 years of therapy, none of the patients had become smear negative and the average BI was 2.56. There was no growth on inoculation of skin-tissue biopsies in the normal mouse foot pad after 6 months of therapy. Bacillemia was still detectable in 11/50 patients, and significant ATP levels were detected in Mycobacterium leprae from skin-tissue biopsies in 16% of the cases. After 3 years of therapy, three patients had become smear negative. The average BI was 1.30. None of the patients had detectable bacillemia, and 5% of the cases showed detectable ATP levels in M. leprae from tissue biopsies. After 4 years of therapy, 41.7% of the patients had become smear negative. The average BI was 0.66, and no ATP was detected in any of the purified bacillary suspensions. The fall in BI was accelerated, and more patients on continued treatment became negative earlier compared to those having treatment for a limited duration, as reported by others.

Adenosine Triphosphate↗
PubMed1989

Application of ATP assay for in vitro drug screening testing against human derived M. leprae.

In this study, the ATP content of M. leprae exposed to various antimicrobial agents has been measured to evaluate its usefulness in drug sensitivity screening. Purified M. leprae suspensions from human biopsies have been incubated at 30 degrees C in a modified Dubos medium in the presence of different concentrations of various drugs viz., Rifampicin, Ethionamide, Ethambutol, Cycloserine, Dapsone, Clofazimine, Erythromycin and Tetracycline. ATP levels were estimated at 0, 7 days, 14 days of incubation by the procedures modified and standardised at this laboratory. ATP decay was accelerated by ethionamide, rifampicin, clofazimine, dapsone, erythromycin and to a lesser extent by cycloserine, whereas ethambutol and tetracycline did not have any significant effect. The rate of decay depended on the concentrations of these drugs. ATP assay promises to be a useful system for in vitro drug sensitivity screening against M. leprae isolated from patients.

Adenosine Triphosphate↗
PubMed1989

Identification of Mycobacterium leprae antigens in tissues of leprosy patients using monoclonal antibodies.

Five monoclonal antibodies (MAbs) directed against antigens of Mycobacterium leprae were tested for their ability to bind to components of tissue sections prepared from biopsies taken from patients with various forms of leprosy. Immunoperoxidase was the most successful marker system used, although immunofluorescence and alkaline phosphatase were also successful in certain cases. Positivity was high with all five antibodies successfully staining those sections containing a bacterial index of 3+ or more; sections with 0 bacterial counts also had areas staining positively with two of the MAbs. The positive staining in the tissues was confined to areas infiltrated by inflammatory cells; however it was not identifiable as being associated with individual bacteria. These findings suggest that immunostaining with specific monoclonal antibodies can help to identify leprosy in diagnostic samples in which acid-fast bacilli are not identifiable by standard histochemical means. Immunohistochemical techniques are likely to be valuable in studies of the distribution of M. leprae antigens and their association with individual tissue elements.

Adolescent↗
PubMed1989

Detection of subclinical infection in leprosy: an 8 years follow-up study.

A follow-up study has been carried out using Fluorescent Leprosy Antibody Absorption (FLA-ABS) test in 1069 healthy contacts of multi and pauci-bacillary leprosy patients. Simultaneously lepromin testing with Dharmendra antigen has also been done to determine their delayed type hypersensitivity. In nearly 8 years of follow-up, 46 contacts have developed disease and of these 41 contacts were FLA-ABS positive and lepromin negative. It is inferred that test (along with lepromin) can be used to identify the contacts who are at higher risk of developing the disease. FLA-ABS test has also been found to be highly sensitive for detection of subclinical infection specially in younger age groups. This test could therefore serve as a very sensitive epidemiological tool for assessing the extent of disease in the community and for monitoring the transmission of disease especially after MDT and other intervention measures.

Adolescent↗
PubMed1989

Dermatoglyphics in leprosy: (III) Creases of palm.

Palmar configurations of triradii and creases of 100 leprosy patients [50 lepromatous (BL/LL) and 50 tuberculoid (BT/LL)] were compared with those of 100 normal persons selected from families of these patients. The patterns of position of triradii were similar in controls and leprosy patients as such. But, the patterns in the two types of leprosy patients were different. As for palmar creases patterns, there was significant difference between those of controls and patients, double radial base crease occurring more often in patients. However, the differences between the two types of patients were not statistically significant.

Dermatoglyphics↗
PubMed1989

Relapses in paucibacillary patients after treatment with three short-term regimens containing rifampin.

Three multidrug regimens all containing rifampin and dapsone have been tried for the treatment of 278 cases of paucibacillary leprosy. Regimen I was the one recommended by the WHO Study Group. Regimen II was the same as Regimen I with depsone alone continued for a further 6 months. Regimen III was the same as Regimen II but rifampin was given daily for the first 7 days. The patients were comparable with regard to disease classification, lepromin status, bacteriological status, and number of lesions. As reported earlier, the disease inactivity rates by 1 year of treatment were much greater with Regimens II and III than with Regimen I (94% and 97% vs 76%). Early reaction was seen in 6% of those in Regimen III and in none in Regimens I and II. Late reaction was observed in 9% of those in Regimen I and none in Regimens II and III. During 3 1/2 years of follow up, 13% of the cases in Regimen I, 1% in Regimen II, and 2% in Regimen III relapsed. Since the patients in the three regimens were otherwise comparable, it is concluded that the high inactivity rate, low relapse rate (1%-2%), and no early or late reaction as observed in Regimen II patients were because of adequate treatment.

Adult↗
PubMed1988

Pyrazinamide as a part of combination therapy for BL and LL patients--a preliminary report.

Pyrazinamide in a dose of 1500 mg was given to 63 borderline lepromatous (BL) and lepromatous (LL) leprosy patients on different drug regimens for the initial 2 months of therapy. Fifty-one BL and LL patients were put on the same drug regimens without pyrazinamide. There was a rapid and good clinical improvement in the patients in both of the groups. At the end of 2 years, the patients who received pyrazinamide had a morphological index (MI) of zero as compared to those patients who did not receive pyrazinamide, some of whom still had solidly staining bacilli. One out of 20 (5%) scrotal (smooth muscle) biopsies of the patients who received pyrazinamide had growth in the mouse foot pad as compared to 9 out of 38 (23.7%) smooth muscle biopsies of the patients who did not receive pyrazinamide. At the end of 5 years, the patients who received pyrazinamide had slightly better results compared with the non-pyrazinamide group. Pyrazinamide appears to have some effect against persisters in multibacillary leprosy. A well-controlled, randomized trial with longer duration of pyrazinamide therapy in a larger group of patients needs to be carried out to unequivocally determine the exact role of pyrazinamide in leprosy.

Adolescent↗
PubMed1987

Appearance of a methoxy mycolate-like component by the acid methanolysis of Mycobacterium leprae.

It has been reported that Mycobacterium leprae contains two types of mycolic acid, namely, alpha- and keto-mycolic acids, thus it is taxonomically similar to M. bovis BCG. However, there was some controversy about the presence of methoxy mycolic acid which was observed in small amounts only in the case of experimentally infected (W45) armadillo-derived M. leprae. To investigate this fact, mycolic acids were extracted from the cell-wall structure of M. leprae and characterized using chromatographic techniques. The results showed the appearance of a methoxy mycolate-like component for both purified bacilli and infected human skin tissue materials. However, this appearance occurred only when the acid methanolysis procedure was followed for the release of mycolic acids from these bacilli. No such component appeared on the chromatogram when the alkaline methanolysis procedure was followed. Nevertheless, the consistent presence of this methoxy mycolate-like component by acid methanolysis is an important finding which has to be kept in mind while identifying this pathogen when using chromatographic techniques.

Chromatography, Thin Layer↗
PubMed1987

Comparison of three regimens containing rifampin for treatment of paucibacillary leprosy patients.

Three regimens containing rifampin have been tried in paucibacillary leprosy patients. The patients were selected according to the criteria laid down by the World Health Organization (WHO). In Regimen I, rifampin 600 mg is given once a month for 6 months with dapsone 100 mg daily. Treatment is stopped at the end of 6 months. Regimen II is the same as Regimen I, and is supplemented with an additional 6 months' treatment with dapsone 100 mg daily. Regimen III is the same as Regimen II, except that rifampin is administered daily for the first 7 days. At the end of the scheduled treatment period, 72.2% of the patients in Regimen I, 94.9% of the patients in Regimen II, and 97.1% in Regimen III became inactive. Eighteen out of the 25 active cases at the time Regimen I treatment was stopped had to be restarted on drug therapy since they showed a worsening of their disease, as indicated by an increase in their bacterial index, the appearance of new lesions, renewed activity in old lesions, an increase in the size of old lesions, or development of nerve abscesses. The remaining seven cases regressed without further treatment. All four Regimen II patients and two Regimen III patients who had evidence of activity at the time treatment was stopped did not require any further treatment. On follow-up for 1 1/2 years, three Regimen I patients and none of the Regimen II or Regimen III patients showed relapses. It is thus apparent that rifampin helps to shorten the time duration and to increase the cost effectiveness of treatment of paucibacillary leprosy cases.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗